UEFI dual boot Installation questions

[carmima]

Hello
I am about to install debian in my new Dell/windows 10 computer
Besides having trouble with Dell computer support service (they charge 100$ USD for software related issues and telling me how to boot from USB stick)
I have questions about dual boot installation. I would like not to loose the windows 10 boot option. after all, it has been paid for it.
What will the installation will do exactly?
I think it will detect the already existing Win 10 Operating System
The actual win10 boot loader is driven by the UEFI.
Will the installer replace the actual boot loader inside UEFI? if so it will be a kind of BIOS update/change?
thank you. I just need insurance before going on installation.
Martin Carmichael

[vmclark]

The best first insurance is to backup your Windows partitions(s). If you are going to re-size the partition don't use CloneZilla.
Read this regarding RST vs AHCI on a Windows install:
https://help.ubuntu.com/rst/
also
https://askubuntu.com/questions/1233623 ... st-systems

I've never been able to install Linux with RST enabled.

[Head_on_a_Stick]

What will the installation will do exactly?
I think it will detect the already existing Win 10 Operating System

Yes, the installer should be able to detect Windows and it should also detect the EFI system partition and mount that under /boot/efi in the installed system. Be sure to enable UEFI mode and disable CSM ("Legacy" mode) in the firmware ("BIOS") options — the installer needs to be booted in UEFI mode for this to work.

You will probably also have to turn off "fast boot" [sic] in Windows, some hardware will disable access to the keyboard & USB devices if it is enabled so you won't even be able to boot the installer ISO image for those machines.

Will the installer replace the actual boot loader inside UEFI? if so it will be a kind of BIOS update/change?

The installer will add a "debian" directory to the EFI system partition and also attempt to add a new NVRAM boot entry for Debian to the top of the UEFI boot order list in the firmware ("BIOS"). Note that some UEFI firmware implementations don't work properly, refer to the relevant link in the Frequently Asked Questions thread from the HowTo section of the forums for ways to work around this problem.

EDIT: and next time buy a ThinkPad instead of Dell's crap. Lenovo store the Windows authorisation key in the firmware so you can wipe Windows and it will be automatically verified if it is re-installed at a later date. Some ThinkPads now have an option to ship without Windows saving £60 off the price.

[carmima]

Thank you all for all recommendations/answers
No, I did not choose to buy this Dell/Hell, and was asthonished by the customer support.
I just inherited from my father who passed out on january 10th
he did made the mistake to buy extended support option from Dell which is ....